libbb: merge mail and uudecode's base64 decoders

function                                             old     new   delta
read_base64                                            -     378    +378
uudecode_main                                        306     315      +9
parse                                                953     958      +5
read_stduu                                           250     254      +4
base64_main                                          217     219      +2
read_base64                                          358       -    -358
decode_base64                                        371       -    -371
------------------------------------------------------------------------------
(add/remove: 2/2 grow/shrink: 4/0 up/down: 398/-729)         Total: -331 bytes

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

6 files changed, 90 insertions, 139 deletions

diff --git a/coreutils/uudecode.c b/coreutils/uudecode.c
index 0da9b09..0c4311f 100644
--- a/coreutils/uudecode.c
+++ b/coreutils/uudecode.c
@@ -13,7 +13,7 @@
 #include "libbb.h"
 
 #if ENABLE_UUDECODE
-static void read_stduu(FILE *src_stream, FILE *dst_stream)
+static void FAST_FUNC read_stduu(FILE *src_stream, FILE *dst_stream, int flags UNUSED_PARAM)
 {
 	char *line;
 
@@ -75,71 +75,6 @@ static void read_stduu(FILE *src_stream, FILE *dst_stream)
 }
 #endif
 
-static void read_base64(FILE *src_stream, FILE *dst_stream)
-{
-	int term_count = 0;
-
-	while (1) {
-		unsigned char translated[4];
-		int count = 0;
-
-		/* Process one group of 4 chars */
-		while (count < 4) {
-			char *table_ptr;
-			int ch;
-
-			/* Get next _valid_ character.
-			 * bb_uuenc_tbl_base64[] contains this string:
-			 *  0         1         2         3         4         5         6
-			 *  012345678901234567890123456789012345678901234567890123456789012345
-			 * "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
-			 */
-			do {
-				ch = fgetc(src_stream);
-				if (ch == EOF) {
-					if (ENABLE_BASE64
-					 && (!ENABLE_UUDECODE || applet_name[0] == 'b')
-					 && count == 0
-					) {
-						return;
-					}
-					bb_error_msg_and_die("short file");
-				}
-				table_ptr = strchr(bb_uuenc_tbl_base64, ch);
-			} while (!table_ptr);
-
-			/* Convert encoded character to decimal */
-			ch = table_ptr - bb_uuenc_tbl_base64;
-
-			if (ch == 65 /* '\n' */) {
-				/* Terminating "====" line? */
-				if (term_count == 4)
-					return; /* yes */
-				term_count = 0;
-				continue;
-			}
-			/* ch is 64 is char was '=', otherwise 0..63 */
-			translated[count] = ch & 63; /* 64 -> 0 */
-			if (ch == 64) {
-				term_count++;
-				break;
-			}
-			count++;
-		}
-
-		/* Merge 6 bit chars to 8 bit.
-		 * count can be < 4 when we decode the tail:
-		 * "eQ==" -> "y", not "y NUL NUL"
-		 */
-		if (count > 1)
-			fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
-		if (count > 2)
-			fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
-		if (count > 3)
-			fputc(translated[2] << 6 | translated[3], dst_stream);
-	} /* while (1) */
-}
-
 #if ENABLE_UUDECODE
 int uudecode_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int uudecode_main(int argc UNUSED_PARAM, char **argv)
@@ -158,7 +93,7 @@ int uudecode_main(int argc UNUSED_PARAM, char **argv)
 
 	/* Search for the start of the encoding */
 	while ((line = xmalloc_fgetline(src_stream)) != NULL) {
-		void (*decode_fn_ptr)(FILE *src, FILE *dst);
+		void FAST_FUNC (*decode_fn_ptr)(FILE *src, FILE *dst, int flags);
 		char *line_ptr;
 		FILE *dst_stream;
 		int mode;
@@ -189,7 +124,7 @@ int uudecode_main(int argc UNUSED_PARAM, char **argv)
 			fchmod(fileno(dst_stream), mode & (S_IRWXU | S_IRWXG | S_IRWXO));
 		}
 		free(line);
-		decode_fn_ptr(src_stream, dst_stream);
+		decode_fn_ptr(src_stream, dst_stream, /*flags:*/ BASE64_FLAG_UU_STOP + BASE64_FLAG_NO_STOP_CHAR);
 		/* fclose_if_not_stdin(src_stream); - redundant */
 		return EXIT_SUCCESS;
 	}
@@ -231,7 +166,7 @@ int base64_main(int argc UNUSED_PARAM, char **argv)
 		*--argv = (char*)"-";
 	src_stream = xfopen_stdin(argv[0]);
 	if (opts) {
-		read_base64(src_stream, stdout);
+		read_base64(src_stream, stdout, /*flags:*/ (char)EOF);
 	} else {
 		enum {
 			SRC_BUF_SIZE = 76/4*3,  /* This *MUST* be a multiple of 3 */
diff --git a/include/libbb.h b/include/libbb.h
index d5580b4..8d7beff 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1505,6 +1505,12 @@ unsigned get_cpu_count(void) FAST_FUNC;
 extern const char bb_uuenc_tbl_base64[];
 extern const char bb_uuenc_tbl_std[];
 void bb_uuencode(char *store, const void *s, int length, const char *tbl) FAST_FUNC;
+enum {
+	BASE64_FLAG_UU_STOP = 0x100,
+	/* Sign-extends to a value which never matches fgetc result: */
+	BASE64_FLAG_NO_STOP_CHAR = 0x80,
+};
+void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags);
 
 typedef struct sha1_ctx_t {
 	uint32_t hash[8];    /* 5, +3 elements for sha256 */
diff --git a/libbb/base64.c b/libbb/base64.c
new file mode 100644
index 0000000..b9d47ae
--- a/dev/null
+++ b/libbb/base64.c
@@ -0,0 +1,78 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright 2003, Glenn McGrath
+ * Copyright 2010, Denys Vlasenko
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+#include "libbb.h"
+
+//kbuild:lib-y += base64.o
+
+void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags)
+{
+/* Note that EOF _can_ be passed as exit_char too */
+#define exit_char    ((int)(signed char)flags)
+#define uu_style_end (flags & BASE64_FLAG_UUEND)
+
+	int term_count = 0;
+
+	while (1) {
+		unsigned char translated[4];
+		int count = 0;
+
+		/* Process one group of 4 chars */
+		while (count < 4) {
+			char *table_ptr;
+			int ch;
+
+			/* Get next _valid_ character.
+			 * bb_uuenc_tbl_base64[] contains this string:
+			 *  0         1         2         3         4         5         6
+			 *  012345678901234567890123456789012345678901234567890123456789012345
+			 * "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
+			 */
+			do {
+				ch = fgetc(src_stream);
+				if (ch == exit_char && count == 0)
+					return;
+				if (ch == EOF)
+					bb_error_msg_and_die("truncated base64 input");
+				table_ptr = strchr(bb_uuenc_tbl_base64, ch);
+//TODO: add BASE64_FLAG_foo to die on bad char?
+//Note that then we may need to still allow '\r' (for mail processing)
+			} while (!table_ptr);
+
+			/* Convert encoded character to decimal */
+			ch = table_ptr - bb_uuenc_tbl_base64;
+
+			if (ch == 65 /* '\n' */) {
+				/* Terminating "====" line? */
+				if (uu_style_end && term_count == 4)
+					return; /* yes */
+				continue;
+			}
+			/* ch is 64 if char was '=', otherwise 0..63 */
+			translated[count] = ch & 63; /* 64 -> 0 */
+			if (ch == 64) {
+				term_count++;
+				break;
+			}
+			term_count = 0;
+			count++;
+		}
+
+		/* Merge 6 bit chars to 8 bit.
+		 * count can be < 4 when we decode the tail:
+		 * "eQ==" -> "y", not "y NUL NUL"
+		 */
+		if (count > 1)
+			fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
+		if (count > 2)
+			fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
+		if (count > 3)
+			fputc(translated[2] << 6 | translated[3], dst_stream);
+	} /* while (1) */
+}
diff --git a/mailutils/mail.c b/mailutils/mail.c
index 8e52a3e..89db661 100644
--- a/mailutils/mail.c
+++ b/mailutils/mail.c
@@ -161,73 +161,6 @@ void FAST_FUNC encode_base64(char *fname, const char *text, const char *eol)
 #undef src_buf
 }
 
-void FAST_FUNC decode_base64(FILE *src_stream, FILE *dst_stream)
-{
-	int term_count = 1;
-
-	while (1) {
-		char translated[4];
-		int count = 0;
-
-		while (count < 4) {
-			char *table_ptr;
-			int ch;
-
-			/* Get next _valid_ character.
-			 * global vector bb_uuenc_tbl_base64[] contains this string:
-			 * "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
-			 */
-			do {
-				ch = fgetc(src_stream);
-				if (ch == EOF) {
-					bb_error_msg_and_die(bb_msg_read_error);
-				}
-				// - means end of MIME section
-				if ('-' == ch) {
-					// push it back
-					ungetc(ch, src_stream);
-					return;
-				}
-				table_ptr = strchr(bb_uuenc_tbl_base64, ch);
-			} while (table_ptr == NULL);
-
-			/* Convert encoded character to decimal */
-			ch = table_ptr - bb_uuenc_tbl_base64;
-
-			if (*table_ptr == '=') {
-				if (term_count == 0) {
-					translated[count] = '\0';
-					break;
-				}
-				term_count++;
-			} else if (*table_ptr == '\n') {
-				/* Check for terminating line */
-				if (term_count == 5) {
-					return;
-				}
-				term_count = 1;
-				continue;
-			} else {
-				translated[count] = ch;
-				count++;
-				term_count = 0;
-			}
-		}
-
-		/* Merge 6 bit chars to 8 bit */
-		if (count > 1) {
-			fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
-		}
-		if (count > 2) {
-			fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
-		}
-		if (count > 3) {
-			fputc(translated[2] << 6 | translated[3], dst_stream);
-		}
-	}
-}
-
-
 /*
  * get username and password from a file descriptor
  */
diff --git a/mailutils/mail.h b/mailutils/mail.h
index bb747c4..e0048fb 100644
--- a/mailutils/mail.h
+++ b/mailutils/mail.h
@@ -32,4 +32,3 @@ void FAST_FUNC get_cred_or_die(int fd);
 const FAST_FUNC char *command(const char *fmt, const char *param);
 
 void FAST_FUNC encode_base64(char *fname, const char *text, const char *eol);
-void FAST_FUNC decode_base64(FILE *src_stream, FILE *dst_stream);
diff --git a/mailutils/mime.c b/mailutils/mime.c
index 44c7d02..682cf45 100644
--- a/mailutils/mime.c
+++ b/mailutils/mime.c
@@ -225,7 +225,7 @@ static int parse(const char *boundary, char **argv)
 	// prepare unique string pattern
 	uniq = xasprintf("%%llu.%u.%s", (unsigned)getpid(), safe_gethostname());
 
-//bb_info_msg("PARSE[%s]", terminator);
+//bb_info_msg("PARSE[%s]", uniq);
 
 	while ((line = xmalloc_fgets_str(stdin, "\r\n\r\n")) != NULL) {
 
@@ -306,7 +306,7 @@ static int parse(const char *boundary, char **argv)
 
 			// dump to fp
 			if (0 == strcasecmp(encoding, "base64")) {
-				decode_base64(stdin, fp);
+				read_base64(stdin, fp, '-');
 			} else if (0 != strcasecmp(encoding, "7bit")
 				&& 0 != strcasecmp(encoding, "8bit")
 			) {